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Video: What is ricin?

WASHINGTON — Ricin, the deadly poison found Monday in the mailroom of Senate Majority Leader Bill Frist’s office, has a long, storied history of use as a weapon of war, terror and assassination and no known antidote.

The U.S. Chemical Warfare Service studied the poison’s potential as a battlefield weapon during World War I; during World War II the British worked on a “ricin bomb,” but it was never deployed.

Ricin is made from the waste byproduct of castor beans in the manufacture of castor oil. Such processing takes place worldwide on the scale of more than 100 million metric tons per year, making the byproduct easy to obtain, according to the American Association of Respiratory Care.

Manufacturing the actual toxin takes no special skills or equipment, experts say. Ricin can be injected, inhaled or ingested; its potential to contaminate the water or food supply makes it particularly nefarious, according to biochemical weapons experts.

Skin exposure to ricin isn’t considered toxic because the amount absorbed through the body is insignificant. To be considered dangerous, ricin would have to be enhanced with a strong solvent such as DMSO, researchers say.

There is no known antidote; however, researchers in academia and in the private sector are working to develop one.

Ingestion is more lethal than inhalation. Through ingestion, “it takes the equivalent of a few grains of salt to kill an adult," said bioterror expert Dr. Michael Allswede, a member of the faculty at the University of Pittsburgh Bio-Security Medical Center in Baltimore.

The danger associated with skin exposure, Allswede said, is from getting it on your hands and then eating something. That’s been the most common exposure in the past, he said. A terrorist would put the ricin on someone’s steering wheel, for example, and the person would get it on his hands and then be exposed while eating.

Exposure to food is the way to contaminate a large number of people; however, “it’s not something very easily done,” says Allswede, who has consulted for the FBI and Justice Department. “There are not many cases where there are large numbers of people eating the same thing at the same time.”

Depending on the route of exposure (such as injection), as little as 500 micrograms of ricin — a dose about the size of the head of a pin — could be enough to kill an adult, a Centers for Disease Control fact sheet on ricin says. A much greater amount would be needed to kill people if the ricin were inhaled or swallowed, the CDC says.

Ricin won’t cause mass casualties; terrorists would most likely use ricin as they would anthrax: in a targeted, closed environment, say terrorism experts.

Real-world ricin
In 1978 a Bulgarian writer, Georgi Markov, was assassinated in London when a foreign agent attacked him with an umbrella that was rigged to inject a ricin pellet under his skin.

In the 1980s there is some evidence that ricin was used on the battlefield during the Iraq-Iran war, and traces of ricin were found by U.S. troops in Afghanistan caves suspected to be al-Qaida hideouts.

In the United States there have been several cases of ricin’s being manufactured and intended for acts of domestic terrorism. From 1991 to 1997 there were three such cases. In 1991 four members of the Patriots Council, an extremist group that advocated the overthrow of the U.S. government, were arrested for plotting to use ricin to kill a U.S. marshal. The ricin they planned to use was cooked in a basement lab and was intended to be mixed with the solvent DMSO and smeared on the door handles of the lawman’s car.

In 1995 Canadian customs officials stopped a man on his way to North Carolina and found he had a container of ricin, along with several guns and nearly $100,000 in cash. And in 1997, while investigating a homicide in which a man killed his stepson, police found ricin being made in a crude basement laboratory in the man’s house.

During the Manhattan trial of four men accused of planning the 1998 bombings of U.S. embassies in Kenya and Tanzania, a training manual, linked to Osama bin Laden’s al-Qaida organization and found in one of the defendant’s apartments, was introduced into evidence. It spoke about how to manufacture and deploy ricin as a weapon of terror.

Since the Sept. 11, 2001, terrorist attacks the FBI has sent out alerts to the private sector asking certain businesses to be alert to anyone shopping for certain ingredients and equipment that could be used in the manufacture of ricin.

Health effects
Major symptoms of ricin poisoning appear within eight hours of exposure, the CDC says, depending on the type and amount of exposure. After ingestion, symptoms can show up in as little as six hours, the CDC says. One of the dangers is that the symptoms aren’t specific to ricin poisoning, medical experts say.

If ingested, ricin can cause vomiting and diarrhea. Severe dehydration may result, followed by low blood pressure, a CDC fact sheet says. Other symptoms can include hallucinations, seizures and blood in the urine. Within several days the liver, spleen and kidneys could fail.

Inhalation would cause the victim to have flulike symptoms: difficulty breathing, fever, cough, nausea and tightness in the chest. This could be followed by excessive sweating as the lungs fill up, making breathing nearly impossible; the skin might turn blue, the CDC says.

Death from ricin poisoning comes within 36 to 72 hours of exposure, the CDC says. “If death has not occurred in three to five days, the victim usually recovers,” the CDC says.

Unlike a toxin such as anthrax, which starts multiplying in the body after exposure, ricin doesn’t grow in the body, said bioterror expert Allswede. “If someone was exposed in the post office yesterday and they’re not sick yet, they’re going to be OK," he said.

The larger question for investigators as they sort through evidence Tuesday is why would someone "send this stuff in a form that wouldn’t be a risk to anybody," Allswede said. “It is a demonstration of capability. It is an intent of the person to say, ‘I can do this anytime, where I want.’”